- Review theories of depression
- Examine the literature on depression and medical illnesses
- Appreciate the different clinical presentations of depression among medically ill
- Learn strategies to provide a differential diagnosis of depression
Introduction The term depression has become an everyday word to describe a state of feeling "blue". People use this word often to describe a negative feeling about events ranging from a relationship breakup to their favorite team losing an important game. Depression can also be part of the grieving process but this is different from clinical depression. Depression, as part of the grief process, tends to diminish over time and does not significantly impair daily functioning for a period of time. In clinical depression, the negative feelings become so overwhelming that daily functioning is impaired. Signs of clinical depression can include sleep and appetite disturbances, fatigue, inability to concentrate, memory problems, decreased sex drive, excessive feelings of guilt, helplessness and hopelessness and sometimes thoughts of suicide. It is, however, a highly treatable disorder, when it is accurately detected and treated. It becomes even more important to treat depression in the medically ill because when depression is left untreated, it can complicate a patient's medical condition and interfere with medical treatments, which ultimately increases the likelihood of mortality.
Although estimates suggest that between 70 and 90 percent of people with depression will seek assistance from their primary care physician (Blacker 1987), 50 percent of the cases will be misdiagnosed and/or under treated. A primary challenge that clinicians face when assessing, treating or consulting about depression is that everyone has his or her own beliefs, expectations and preconceived notions about the disorder. In part, this stems from the fact that the word is commonly used in everyday language as well as in the clinical arena. Seldom do people ask for clarification when they hear the term depression as they may if you were discussing schizophrenia or hypothyroidism. This is partly due to the lack of specificity in the language that we use. In some languages, for example, there are several different words that further describe an expression of an idea or concept. A language that is highly specific and allows for the expression of abstract and complex ideas improves communication. Despite the high incidence of depression in this culture, our language frequently lacks the specificity for discussing this all too prevalent condition of depression. For example, the very same word is used to describe everything from momentary sadness to all pervasive despair. At the same time that we may describe a situation as depressing or a mood as feeling depressed, depression is also a clinical diagnosis.
As a result, depression can be a fuzzy concept with connotations and consequences that vary from person to person. For some the word "depression" implies a weak moral character, the cure for which is that the depressed person must "simply get it together". Consequently, patients may feel uncomfortable discussing their feelings for fear that they will be viewed as weak or that the condition is not worth bothering the physician about since it is not something that can be medically treated (Katon, 1987). This situation is further exacerbated by the fact that physicians and other health care providers often see depression as an expected and understandable psychological reaction to a medical illness or to a stressful life event. They therefore inadequately treat the symptoms of a serious depression, which, in turn, can complicate a medical condition. (Popkin 1988).
Before one can discuss treatment of a disorder, attention must be given to the theories of what causes and exacerbates it. There are many different theories and explanations for what causes depression. Depression among the medically ill is even more complex when we factor in the medical condition as a cause and contributing factor. The following section briefly summarizes three primary theories of depression. Realize that the causes, risk factors, and contributing factors can vary person-by-person and depressive episode by depressive episode. Therefore, an understanding and incorporation of each of the theories is important if comprehensive treatment is to occur.
Theories of Depression
Biological Theory Nerve cells or neurons communicate to one another through chemicals, called neurotransmitters. The place at which the neurotransmitters are released is called the synapse. The synapse is a small space that exists between two nerve cells, which are very close but do not touch. At the synapse, a transmitting neuron, known as the presynaptic neuron emits a small amount of the neurotransmitter to the postsynaptic or receiving neuron. A typical neuron receives thousands of messages from other neurons each at a different synapse and some of these messages are inhibiting while others are stimulating. When the balance of stimulating messages that one neuron receives passes a threshold, the neuron "fires" this in turn stimulates the neurons to which it is transmitting.